[ICE: 12] Router fee for slow path

[ekbainova]

Describe the bug UI is calculating router fee although already shows a slow path ETA. It doesn’t make sense that the UI calculates the router fee if it will go through the slow path. If txn goes through the slow path, the router fee should be 0

To Reproduce Steps to reproduce the behavior:

1. Go to 'https://bridge.connext.network/EZETH-from-arbitrum-to-ethereum?amount=122222'
2. Click on 'Additional details'
3. See error

Screenshots

[ekbainova]

https://app.intercom.com/a/inbox/qge2vd8z/inbox/admin/7092575/conversation/1126?view=List

[just-a-node]

Router fee is not only estimated here but also charged in the actual transaction.

[just-a-node]

@ekbainova It isn't always the case that a slow-estimated transfer will go slow. If we estimate slow and it actually goes fast, then the router fee will be charged on destination. Given this, we cannot always guarantee a 0-router fee transfer even if we estimate it will be slow. I think our best option is to further set expectations around this - e.g. we make it clear to users that it's only an estimate and that if their transfer goes fast, they will incur the router fee.

Passing back to you to determine how we should handle this.

[ekbainova]

Did we fix it?

[jwtong]

There wasn't a proposed fix yet. Need some guidance on how to solve the dichotomy in presented info

[ekbainova]

We should think about UI warning explaining how fast path works and warning about possible router fee even with slow path. NOTE: this router fee is taken from received amount and it will be charged only if router boost it.